Insert sustain pedal, mod wheel, expression swells, pitch bend, or aftertouch into a REAPER MIDI item at precise positions.
Adds controller events: sustain pedal, mod wheel, expression swells, pitch bend.
| Name | Required | Description | Default |
|---|---|---|---|
| events | Yes | ||
| channel | No | ||
| item_id | Yes | MIDI item id from create_midi_item/get_track_details, or "selected" |
Changes observed during successful MCP inspections.
v0.19.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden, and it says nothing beyond 'adds'. It does not state whether events append to existing CC data or overwrite, whether the item must already exist, channel defaulting, or any failure/return behavior for this mutation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single efficient sentence with the verb front-loaded and no filler. It is a fragment rather than a full sentence, but every word earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a mutation tool with no annotations, no output schema, and only 33% top-level schema description coverage, the description should disclose more: the 'selected' magic value for item_id, the meaning of the channel default, and append-vs-overwrite semantics. As written it is too thin to call the tool confidently.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is low (33%), but the nested CCEvent definition documents cc, value, and position in detail. The description partially compensates by naming controller types that map to the cc parameter (mod wheel, expression, sustain, pitch bend). It adds no meaning for item_id, channel, or how events are ordered.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource ('Adds controller events') and enumerates representative cases (sustain pedal, mod wheel, expression swells, pitch bend), so the agent knows exactly what class of MIDI data it writes. It does not explicitly distinguish itself from the sibling family get_midi_cc / delete_midi_cc, but the verb makes the intent unambiguous.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No when-to-use, when-not-to-use, or alternative guidance. It never states the prerequisite that item_id must come from create_midi_item/get_track_details, nor that get_midi_cc should be used first to inspect existing controllers. The agent must infer all usage context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.